Railway signal control system



w. H. cLAus RAILWAY SIGNAL, CONTROL SYSTEM Nov. 11, 1952 Filed F'eb.- 11, 1948 2 SHEETS-SEER? 1 IN V EN TOR. f1. Llaas.

HIS

NOV. 11, 1952 w, c us 2,617,920

RAILWAY SIGNAL CONTROL SYSTEI Filed Feb. 11, 1948 2 sxms'rs-srzsw 2 av 12 W 10s I? Hi y h I A r: 67' :7s 77 QED}? I 5 H n i6;

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INVENTOR. fly Ib PVZ'ZZHI Claus.

BY I

HIS arrow? Patented Nov. 11, 1952 UNITED? STATES sis-r sari @FFIC s:

s a rway SIGNAL CONTROL SYSTEM William H; Clans, Downers GroIveJlli, assig'nor'to Westin-ghous'e- Air Brake Company, .axcolfnorattion of-Pennsylvania Application-February 11, IMSQ-SeriaINog755 3 Gl'ain s;

My invention relates to amrailway signal control system, and particularly to a' railway sign l o rol s s fo sn ls o eover 'ngtr fie, m ements in oppo i .cl ectilo j ov stretch of single track railway.

In a railway signalingfsystem' of the wellknown absolute permissive block" type for a V stretch of single trackrailway which-is provided with passing sidings spacedalongthesingle track,

viding overlapping control for; the signals for one direction onlyof trafficmpllements, and for at other t p o d n Ove la .ns c ntrol" for the signals for the opposite direction only of traffic movements,

I shall describe one formi'of' apparatus embodying my invention;-and shall then pointout'the novel features thereof in-claims.

The accompanying drawings, Figs. la'and 12), when placed side by side, with Fig; la on the left, constitute a diagrammatic viewshowing one formuof apparatus embodying my -inventio'n,in whicha stretch of single track railway is provided with passing sidings spacedialong the single track-railway ,and in Which, two pairs of head block signals are employed for'each passing s'id+ ing and are placed-one pair adjacent .each endof each passing siding, and one pair of intermediate signals is remployedbetween' consecutive passin sidings for governing trafiic movements in opposite directions; and-in which manually controllable vaparatus is provided: for arranging overlap control for the signals for only onedirection or the other at any given time.

Similar reference characters refer to. similar parts in each of the drawings.

In each of the drawings, thepcontacts operated by the various relays orwother devices are identified by ,numbers,"each such number having a distinguishing prefix, from"; which it is separated by a dash; when the associated Contact is shown Protection or wstl l id direction."

2, pa t from the relay by which his 10pe ated- The prefix for each of these contactnumbers omprises t e re e ence cha acter .iqr the eo tivesre y by-wh ch the assoc a ed. onta t is o rated For examp e c n r L s w or tales W12 i separated by a is identified-by the number 2'! dash from the p refiizisftlwhich is there-ference character for relay ZSRI'b'y' which this contact isoperated.

of "asingl'e track"railwa shown provided with passin'gi'sidin 's X and W; Inorderflto' simplify the drawin -s; each"it c comprisin wo pa al 'e seriesof rails sren e jented 'by a sinsl' ine-j a Theportionf ,of the single ftrac'l; r lway shown in the' drawi.n' s is divided primat s joints H to form sections, each of is. designated yth r f r nce .0; a te Ifpr ced d'by a stin uishing e'ril al" n fix- Ea h .of' t rack sections is pr ded withatrack'circuit includin a suite. sourceof urre t, s ch as aba y I2, co nec ed arr sti elrailsya acent do thes c mmwd a r ckr y, des d y t eferencec aracter ht dis u s e prefix, c nnected a oss he rails jacent the opposite nd of the section;

Adjac nt each 'of'leach 'ofythepassing s ding Ztraffic' movemen -s n opposite d rectio Si naIsZS, 38; 8S, and '93, which govern traffic movements away from the paSSing-sidings, are" known ,as leaving signals; whereas signals IS,

1 d8, flS QYand 10S, which govern eme movement's toward thefpassing si-diiig'sfare known as enter ing signals; one, pair ofinternidiatesignals, 5S and 6S; governs traffic'movinents inlopp'dsite directions between th two consecutive passin siding-s. Signals .IS, as, ,5sp1s amiss govern trains movements-toward the right," as shown in the draw ngs, which 1 shall assume is the east; boundnire'ctioh; whereas signals zs'fas, as; as, and 16S govern 'trafiic' movements i the opposite any suitable 'uefsigri' such", 'for "example; 'as the color light type shown: 'in' tthehrsmhg each of which comprises a green ior'l clear lamp G, a Lyelflowor caution lamp Y, and fa red or stop-minis R.

Eachoffthesiei alsisignal relay JHDRZ' h "vin whichfisjthe same ei 'enp h t si arrelajysilinR. has'fla frele'ase neutral armature, and therefore its" front contacts re- 4 a nume risn me" he numerical prefixin the The signalsm'ay be of ontrolled Joya polarized its signal. Each of the main closed while its polar contacts are moving between their extreme positions. Each of the relays HDR is energized by current of normal or reverse polarity from a suitable source such, for example, as batteries IQ and 2Q shown in the lower left-hand portion of Fig. 1a having a positive terminal B, a negative terminal N, and a common terminal C. The G, Y, and R lamps of each signal are lighted by circuits which are controlled by the associated signal relay, and which are similar to the circuits shown for si nals 4S and 88.

A polarized block repeater relay TP which has a slow release neutral armature is controlled by front contacts of relays 3TB, TR, and B'I'R for the stretch of single track which includes sections 3T, ST, and BT between the pair of head block signals 38 and 48 adjacent the east end of siding X, and the pair of head block signals IS and BS adjacent the west end of siding W. The polarity of energizaticn of relay '1? is controlled by relay AHDR.

Block stick relay TPS and a time element device T'I'E are controlled by a front contact of relay TP. Relay TPS is also controlled by time element device T'I'E, which may be of any suitable design such, for example, as the thermal type shown in Fig. 1b of the drawings.

A manually operable overlap control lever, designated by the reference character ZV, has a normal control position n and a reverse control position 1. Contacts operated by lever ZV are shown as circles, in which are placed reference characters to show the positions of the lever in which the contacts are closed. Contact 64, for example, of lever ZV is closed when and only when lever ZV is in its reverse position 1*.

A polarized overlap control relay ZR is controlled by lever ZV and by relay TPS. Relay ZR is energized by current of normal polarity if lever ZV is inits normal or 1 position, and relay ZR is energized by current of reverse polarity if lever ZV is in its reverse or 1' position.

A neutral overlap indication relay ZP is energized in series with the winding of relay ZR.

A neutral overlap control relay ZRP is controlled by a normal contact of relay ZR.

Relay ZHDR may be controlled in any suitable manner by traific conditions west of signal 2S. Relay QHDR may be controlled in any suitable manner by traffic conditions east of signal An energizing circuit for relay GHDR includes front contacts of relays ITR and ZTR, so that relay iHDR will be deenergized when either of the relays ITR and 2'IR is deenergized. The polarity of energization of relay 4HDR is controlled by relay ZI-IDR;

Relay GHDR is controlled by a circuit which includes front contacts of relays AHDR, 3TR, and 5TB. Whenever either track section ST or ST is occupied by a train, causing relay 3TB or relay BTR, respectively, to be deenergized, relay BHDR will be deenergized. As shown in Fig. 1a, an auxiliary circuit path is closed around contact [9 of relay AHDR through contact of neutral overlap control relay ZRP, so that when contact 20 of relay ZRP is closed, relay EHDR will not become deenergized when relay liHDR becomes deenergized on account of relay ITR or 2TR being deenergized. If, however, relay ZRP becomes deenergized, so that its contact 20 becomes opened, relay BI-IDR will become deenergized when either relay ITR or'2TR be- 4 comes deenergized, as well as when either relay STR or BTR becomes deenergized.

Relay 8HDR is controlled by a normal control circuit which includes front contacts of relays BHD'R and S'I'R. This circuit for relay SHDR will therefore b opened if either relay ITR or 2TR is deenergized while relay ZRP is deenergized, as well as when any one of the track relays 3TB, 5TB, and 8TR for the stretch of track between the pair of head block signals 38 and 4S and the pair of head block signals IS and BS is deenergized.

Relays 'IHDR, 5HDR, and EI-IDR are controlled by track relays similarly to relays 4HDR, BHDR, and BHDR, respectively, as just described. The polarity of energization of relay 'IHDR is controlled by relay SHDR.

Polarity control relays lPCR and 'IPCR are controlled by front and normal polar contacts of relays AHDR and. lI-IDR, respectively. Relays 4PCR and 'IPCR control the polarity of energization of relays SHDR and 5HDR, respectively.

A direction stick relay 5SR associated with.

signal 55 is controlled in a well-known manner: to become energized when an eastbound train. enters section 5T while a front contact of relay- EHDR is closed, and to then remain energized. by circuits controlled by back contacts of relays; ETR and 5HDR. A direction repeater relay ESPR is controlled by a front contact of relay; 5TB and by a back contact of relay 58R. A. second direction stick relay GSR and a second direction repeater relay GSPR for westbound traffic: movements are controlled similarly to relays ESR;

and 5SPR, respectively.

An overlap stick relay ZSR is controlled by a;

thermal type, and by front contacts of relays. 'lI-IDR, 8I-IDR, and ZR, and also by a back contact.

of relay TPS. Contacts of relay ZSR ar in-- cluded in control circuits for relays SHDR anda BHDR in order to delay the clearing of either signal 58 or 8S, respectively, for a measured pe-- riod of time after the other of these signals has. been controlled by lever ZV to indicate stop.

Overlap indication lamps nZK and TZK are controlled by overlap indication relay ZP and by lever ZV. Track occupancy indication lamps l-ZTK and 358TK are controlled by relay TP, and track occupancy indication lamp 1-9TK is controlled by relays ITR and 9TB.

Having described, in general, the arrangement and control of the apparatus shown by the accompanying drawings, I shall now described, in detail, its operation.

As shown in the drawings, all parts of the apparatus are in their normal condition, that is, each signal is displaying a green or clear indication; lever ZV is in its normalor 11. position; all track sections are unoccupied, and hence all track relays are energized; each signal relay HDR, block repeater relay TP, and overlap control relay ZR are energized by current of normal polarity; each of the relays 4PCR, 'IPCR, ZRP, ZP, 5SPR, BSPR, TPS, and ZSR is energized; each of the relays 58R and GSR is deenergized; indication lamp nZK is lighted; and the other indication lamps are not lighted.

The circuit by which relay lHDR is energized by current of normal polarity passes from terminal B of battery IQ, through the front point of contact l3 of relay ZHIDR, contacts l4 and I5 of relays ZTR and ITR, respectively, and the winding of relay ll-IDR to terminal C of batteries lQ '3 and 2Q Relay THDRI is energized by-asimilar circuit.

Relay tPGR is" energized by a circuit passing fr-zsmterminal B; through contacts Iii and I 1 of relayflHD' R, and thewinding' of relay JPCR' to terminal C; Relay' lP'CR is energized by a circuit which is similar tc' that just'trac'ed for rel'ay weltv .p

The circuitb'y which relay smears-energized bycurrent of normal polarity passes fromterminal B; through the front point of contact [8 of relay lPCR, contact [9' of rblaydI-DJR-ihmultiple with contact 2 0 of relay ZRP; contact -2l of relay 3TB, contact 22 of relay 5TR, and thewinding ef'relay snna tdtefr'minal o: i

A pick-"up circuit isclosed for energizing relay BHDR by current of normal polarity,- this circuit passing from terminal B, through ntact 23 of relay 6I-IDR, back point or contact 24 or relay csaco'ntact 25 of relay Esra, contact 2'6 of-relay 8TB; contact ZSR-Z'l, and the winding of relay lil-IDRtotermihal C. A stick circuit is also closed for relay 8HDR, which is the same as the pick-up circuit just traced excep'tthat it includes contact 280i relay 8HDR insteadf contact ZSRJ-Z-l.

Relay EHDR is energized by currentof hor mal polarity passing from tenninal- B, through the front pointof contact 29 of relay TPCR, contact 39 of relay lHDR, Contact 33 of relay 3TB, contact M of relay TH, and the winding-of'relay liHDR to terminal 0.

Relay tl-lDR is energized by current of-normal polarity passing from terminal -B, throug-h contact 35' of relay-eHD-R, back point of contact 35 of relay 5SR,contact 3lof relay BSPR, contact 38 of relay 3TB, and the winding-'of'relaytI-IDR to terminal 0.

The green lamp G of signal 548 islighted by current passing from terminal EB of a suitable l source of lighting current, through front point of contact 39 of relay QHDR, contact 40 of relay iI-IDR closed in the normal or left-hand position, and lamp G to terminal EN of the same source of lighting current. Green lamp G of each of the other signals is lighted by circuitswhich are similar to that just traced for signal 48.-

Direction v repeater relay BSPR is energized by a circuit passing from terminal Bithro'ugh contact 4| of relay ESE, contact-42- of relay 5TB, and the Winding of relay BS'PR to terminal C. Relay liSPR' is energized by a similar circuit.

Relay IP is energized by current of normal polarity passing from terminal B through the front point of contact 44 of relay 4HDR, contact t5 of relay 3TB, contact lfi of relay 5TB, contact 4'! of relaytTR, and the Winding of ielay TP to terminal C.

Relay TPS is energized by a stick circuit passing-from terminal B, through contact 48 of relay TP, front point of contact #9 of relay T'PS, and the winding of relay TPS to terminal C.

Overlap control relay ZR and overlap indication relay ZP are energized in series with each other by current ofnormal polarity passing from terminal B, through contact 5| of lever ZV, winding of relay ZP, contact 52 of relay TPS -and the winding of relay ZR to terminal C. R

Relay ZRP is energized by a circuit passing from terminal B, through contact 54 of relay ZR, and the winding of relay ZRP to terminal C.

A'sti'ck circuitfor relay Z'SR, is closed, passing from terminal 13, through contact 55 of relay BHDR, Contact at of relay IHDR, front point of contact 5970f relay Z SR, and the winding of relay ZSR- to terminal C. A second stick circuit is also drawings thus in' the normal-condition, an eastbound train approaches-signal IS and cleenergi zes reIay ZI-IDR; causing green lamp G of signal '23 to be extinguished, and causing redlamp of this sig-nal to be lighted by a circuit which is similar to the circuit traced forlamp R- of signal 4S.-

With relay Z HDR deenergized, relay 4HDR will now be energized" by current of reverse polarity passing from terminal'C, through the 'windingof relay lI-IDR, contact I5 of relay ITR,

contact M of relay 2TB), and the back point of contact I 3 o'frelay Z'HDR to terminal N of battery 2Q. With relay-HIDE energized by current of reverse polarity, g'reenlamp G of signal 48 will be extinguished, and lamp Y of this signal will become lighted by a circuit passing from terminal EB, through the front point of contact 39 0f relay ll-IDRL, contact 40 of relay 4HDR in the reverse position, and lampY of signal' lS to terminal EN.

When relay'AHDR becomes'e'nergized by current of reverse polarity, its contact I! opens the circuit previously traced for relay 4PCR, causing relay 4PCR to become deenergized.

With relay 4PCR deenergized, relayGHDR is energized by current of reverse polarity'pass'ing from terminal 0 through the winding of relay SI-IDR contact 22 of relay 5TH, contact 2| of relay 3TR, -contact l9 of relay 4HDR in multiple with contact 20 of relay 'ZRP, and the back point of contact I 8 of-relay 41 GB to terminal N. With relaytHDR thus energiz'edby current of reverse polarity, green lamp G of signal 68 will be extinguished, and yellow lamp Y of signal 68 will be lightedby a circuit which is similar to the c'ircuit previously traced for signal 48.

When the eastbound train enters sectionzT, contact I 4 of relay 2TH opensthe circuit previously traced for relay causing relay AHDR to become deenergized. With relay 4HDR deenergized, yellow lamp Y of signal 4S becomes extin'guished and red lamp R of this signal becomes lighted by a circuit passing from terminal EB, through the back point of contact 39 of ,relia'Ny 4HDR, and lamp R of signal 45 to'terminal Contact IQof-relay 4HDRis now open in the circuits tr'aced-forre-lay GI-IDR which, however, remains energized by current of reverse polarity because contact "20 of relay ZRP isstill closed.

With relay 4I-IDR deenergized, relay '1? is energiz'ed by current of reverse polarity passing from terminal C through the winding of relay TP, contacts 47,146 and 45 of relays 8'TR, 5TR., and 3TB,- respectively, and the back point of contact 44 of relay-dHD R; to terminal N. Relay TP, upon becoming energized by current of reverse polarity, completes a circuit for lighting lamp LZ TK, this circuit passing fromnterminal EB, through the front point of contact $5 of relay TP, contact 6 6 of relay TP, and lampI-TTK to terminal EN.

When the train leavesseotion 2T, relay -2HDR again becomes energized, causing lamp R of signal 2S tobecome extinguished and lamp G of this signal to become lighted by a circuit which is similar to the circuit traced for signal 48. Relay AI-IDR, however, now remains deenergized because its circuit is open at contact [5 of relay l'I'R.

When the train enters section 3T, contact 38 of relay 3TR opens the circuit traced for relay 3l-IDR, causing relay 3HDR to become deenergized. Contact 21 of relay 3TB also opens the circuit for relay BHDR, causing relay GHDR to also become deenergized. With relay 3HDR deenergized, green lamp G of signal 38 becomes extinguished, and red lamp R of this signal becomes lighted; With relay BHDR deenergized, yellow lamp Y of signal 68 becomes extinguished, and red lamp R of this signal becomes lighted.

With relay EHDR deenergized, the circuit previously traced for relay 8I-IDR becomes opened at contact 23 of relay 6HDR, causing relay 8HDR to become deenergized. With relay 8HDR deenergized, green lamp G of signal 88 becomes extinguished, and red lamp R of this signal becomes lighted by a circuit which is similar to the circuit previously traced for signal 48.

With relay STR deenergized, relay TP is now deenergized on account of contact 45 of relay 3TR being open. With relay TP deenergized, indication lamp i-2TK becomes extinguished, and lamp 3-5-8TK becomes lighted by a circuit passing from terminal EB, through the back point of contact 65 of relay TP, and lamp 3-5-8TK to terminal EN.

Relay TP, upon becoming deenergized, permits its contact 48 to open, thereby deenergizing relay TPS.

Relay ZR, therefore, now becomes deenergized because contact 52 of relay TPS becomes opened. Relay ZP, which is in series with relay ZR is also deenergized, and therefore its contact 6| opens the circuit previously traced for lamp nZK, causing this lamp to be extinguished.

Relay'IPS, upon becoming deenergized, completes a third stick circuit for relay ZSR, this circuit passing from terminal B, through contact TBS-58, front point of contact 59 of relay ZSR, and the winding of relay ZSR to terminal C. Relay ZSR, therefore, remains energized because contact TPS-58 becomes closed before contact 51 of relay ZR opens, and also before contact 55 of relay BHDR opens the first stick circuit traced for relay ZSR.

When the train leaves section IT, relay 4HDR again becomes energized by current of normal polarity, causing lamp R of signal 48 to become extinguished, and lamp G of this signal to again be lighted. With relay 4HDR again energized by current of normal polarity, relay 4PCR again becomes energized by its circuit previously traced.

When the train enters section 5T, contact 34 of relay 5TR opens the circuit previously traced for relay EI-IDR, causing this relay to become deenergized. With relay EI-IDR deenergized green lamp G of signal 58 becomes extinguished, and red lamp R of this signal becomes lighted.

When relay 5TR becomes deenergized. its contacts 42 and 43 open the circuits for relays SSPR and GSPR, respectively, causing these relays to be deenergized.

Because the neutral armature of relay 5HDR is slow in releasing, its contact H remains closed for a brief period of time at its front point after relay EHDR becomes deenergized. Relay SSR, therefore, becomes energized by its pick-up circuit passing from terminal B, through contact Hi of relay 5TB, front point of contact H of relay 5HDR, and the winding of relay 5SR to terminal C. Relay 5SR, upon becoming energized, completes a first stick circuit passing from terminal B, through contact 10 of relay 5TB, contact 12 of relay 58R, and the winding of relay 58R to -terminal-C. When relay 5HDR releases its neutral armature, a second stick circuit becomes closed which is the same as the first stick circuit already traced for relay 5SR except that it includes the back point of contact H of relay EHDRinstead of contact 10 of relay 5TR.

When the train enters section 8T, causing relay ETR to become deenergized, contacts 26, 33 and 41 of this relay become opened in the circuits for relays 8HDR, 5HDR, and TP which are, however, already deenergized because relay 5TB. is deenergized.

When the train leaves section 5T, relay BSPR again becomes energized by its circuit previously described. Relay 3HDR, therefore, now becomes energized by current of reverse polarity passing from terminal C, through the winding of relay EHDR, contact 38 of relay 3TR, contact 3'! of relay BSPR, and the front point of contact 36 of relay 5SR to terminal C. With relay 3HDR energized by current of reverse polarity, lamp R of signal 33 becomes extinguished and lamp Y of this signal becomes lighted. When the train leaves section 5T, relay BHDR again becomes energized by current of normal polarity, causing lamp R of this signal to be extinguished and its lamp G to be lighted.

When the train enters section VI, deenergizing relay 'ITR, relay 'lI-IDR becomes deenergized, causing lamp G of signal IS to be extinguished, and lamp R of this signal to be lighted. With relay 'ITR deenergized, indication lamp 'I-QTK becomes lighted by a circuit passing from terminal EB, through contact 67 of relay 'ITR, and lamp l- TK to terminal EN.

When the train leaves section 8T, relay TP again becomes energized by current of normal polarity in its circuit previously traced. With relay TP energized, a circuit is completed for energizing time element device TTE, this circuit passing from terminal B, through contact 48 of relay TP, back point of contact 49 of relay TPS, and the control element of time element device TTE to terminal C. Upon the lapse of a measured period of time, contact 50 of time element device TTE completes a pick-up circuit for relay TPS, this circuit passing from terminal B, through contact Q8 of relay TP, contact 50 of time element device TTE, and the winding of relay TPS to terminal C. Relay 'I'PS, upon becoming energized, completes its stick circuit previously traced.

Since relay TPS does not become energized until the lapse of a measured period of time after relay TP becomes energized, relay ZSR remains energized by its third stick circuit previously traced l u h that relay sHDR. becomes energized by its pick-up circuit previously traced.

When relay TPS becomes energized, relays ZR and ZP again become energized by their circuit previously traced. With relay ZP again energized, lamp nZK again becomes lighted by its circuit previously traced.

When the train enters section 9T, relay 9HDR becomes deenergized, causin lamp G of signal 93 to be extinguished, and lamp R of this signal to be lighted.

While the train is moving through sections IT and ST, relay HDR remains deenergized because contact 30 of relay 'IHDR is open and contact 3| of relay ZR is open. Signal 55, therefore, continues to indicate stop.

When the train leaves section .ST, relay iI-IDR becomes energized by current of reverse polarity, causing lamp Y of signal .ISto be lighted. With relay 'IHDR energized by current, of reverse polarity, so that relay 'IPCR is deenergized, a circuit is completed for energizing relay EHDR by current of reverse polarity, this circuit passing from terminal 0, through the winding of relay EHDR, contact 34 of relay 5 B, contact 33 of relay 8TB, contact 30 of relay lHDR, and the back point of contact 29 of relay TIPCR to terminal N. Yellow lamp Y of signal 53, therefore, now becomes lighted. With relays 5TB and 5HDR now both energized, relay ESR becomes deenergized, and hence the circuit is again completed for energizing relay SI-IDR, by current of normal polarity. Green lamp G ofsignal 38, therefore, now. becomes lighted.

I shall next assume that. all parts .of the apparatus are again in the normal condition, and that an eastbound train passes signal IS and is approaching signal 3S. I shall also assume that a westbound train deenergizes relay 9TB, so that signals 95 and is are indicating stop. With re.- lay 'IHDR deenergized, contact. 30 of this relay is open in the circuits previously traced for relay EHDR, so that relay 5HDR becomes deenergized, causing relay 3HD-R in turn to also be deenergized. Signals 5S and 38 also Will therefore indicate-stop.

I shall assume further that the two trains are to pass each other with the eastbound train moving onto passing siding W, while the westbound train remains on section 1T of the main track.

A leverman or dispatcher therefore moves lever ZV to its r position for energizing relay ZR by current of reverse polarity for thereby rendering ineffective. the overlap control of relay BI-IDR. through contact 30 of relay 'lHD-R. The circuit by which relay ZR becomes. energized by current of reverse polarity passes from terminal C, through the winding of relay ZR, contact 52 of relay 'IPS, winding, of relay ZP, and contact 53 of lever ZV to terminal N. Lever ZV, upon being moved to its. '1" position, -extinguishes lamp 'nZK, and then completes a circuit passing from terminal EB, through contact 63 of relay ZP, contact 64 of lever ZV, and lamp. TZK to terminal EN, causing lamp rZK to now become lighted.

With relay ZR energized by :current of reverse polarity, its contact 54 opens the circuit for relay ZRP, causing contact 23 of relay ZRP to become opened. With the eastbound train on section IT, relay M-IDR. is also deenergized, and therefore contact 19 of relay dI-IDR, as Well as contact 2d of relay ZRP, is open, causing relay fiI-IDRto become deenerg'ized. With relay GHDR deen-ergized, its contact 23 opens the circuit for relay I8H DR, causing relay fiHDR to also be deenergized. With relays enna and BHDR now both deenergize'd, signals 63 and 88 are both displaying the red or stop indication.

The neutral armature of relay ZR, is not of the slow releasing type, and therefore when lever ZV 'is moved from its 'tofits 1' position, contact 5'! of relay ZR becomes opened, so that relay ZSR becomes deenergized because its first pick-up circuit is already open at contact 56 of relay IHDR, and its third pick-up circuit is open at contact TPS-EB. Contact ZSR-32 is therefore 10- opened in the auxiliary circuit path around contact 3d of relay 'IHDR.

After contact 3! of relay ZR becomes closed, contact 51 of relay ZR again becomes closed, thereby completing a circuit for energizing'time element device ZTE, this circuit passing from terminal B, through contact 5? of relay ZR, back point of contact 59 of relay ZSR, and the control element of device ZTE to terminal C Upon the L lapse of a measured period of time, a pick-up circuit becomes closed for relay ZSR, passing from terminal B, through contact 5'! of relay ZR, contact 66 of time element device ZTE, and the winding of relay ZSR to terminal C.

Relay ZSR, upon becoming energized, CGll1- pletes a circuit for energizing relay E-HDR by current of reverse polarity, which is the same as the circuit previously traced for energizing this relay by current of reverse polarity except that it includes contact ZSR-32 and contact i i of relay ZR instead of con-tact (it of relay ii-113R. With relay 5HDR energized by current of reverse polarity, yellow lamp Y of signal 553 will now be lighted, and relay EHDR-wili become energized by current of normal polarity, lamp G of signal 3S to be lighted.

From the foregoing description, it follows that because of the timed element control of relay ZSR when lever ZV is moved from its a to its 1" position for causing signals 8S and ES. to display the stop indication, signal 35 will not at once be controlled to display the green indication, but will continue to indicate stop for a measured period of time. The eastbound train will then pass signal 38 displaying a green indication and signal 5S displaying the yellow indication.

When the eastbound train moves. onto passing siding W and leaves section 8T, relay 5HDR will again become energized by current of reverse polarity in the circuit through contact di of relay ZR, and relay 3HDR Will again become energized by current of normal polarity. Signal 58, therefore, will again display the yellow indication, and signal 3S will display the green indication.

I shall now assume further that a second leastbound train has entered section 21 and is approaching signal is. Relay iHDR is, therefore, deenergized. Contact 19 of relay AHDR, will therefore be open, as well as contact '29 of relay ZRP, so that relay SHDR will remain deenergized,

and therefore relay 'BHDR, will also remain deenergized, so that signals {is and d's'willcontinue to indicate stop after the first eastbound train leaves section 81'. I

I shall assume, however, that the dispatcher decides to have the westbound train and the second eastbound train pass each other at passing siding .X. He will, therefore, return lever ZV to .its .n position after the first eastbound train has left section 8T. Relay ZR will, therefore, again become energized by current of normal polarity and will open its contact 31, thereby deenergizing relay EHDR. which in turn deenergizes relay 3HDR,;causing signals 55 and ES to again displaythe stop indication Withv relay ZR again energized by current ,of normal polarity, relay ZRP is again energized by its circuit previously traced, so that relay EHDR, is again energized by current of reverse polarity, gausing signal 68 to display the yellow indicaion. 7 i

Movement of lever ZV from its r to its 11 position causes contact 5'! of relay 'ZRto open the stick circuit for relay ZSR, so that relay ZSR becomes deenergized, and therefore relay BHDR cannot become energized by its pick-up circuit until relay ZSR again becomes energized after the lapse of a measured period of time for energizing time element device ZTE: after the completion of the movement of lever ZV to its n position.

It follows that, after the dispatcher causes si nals 3S and 58 to indicate stop by the movement of lever ZV from its 1' to its n position, a measured period of time must elapse before signal 88 will clear. One purpose of relay ZSR and its time element device ZTE is to accomplish this result.

If, under the conditions just described, the dispatcher, instead of waiting until the first eastbound train leaves section 8T, returns lever ZV to its n position while the first eastbound train is on section 8T, relay ZSR will remain energized by its stick circuit including contact TPS-58 as long as relay TPS remains deenergized. During the period of time required for time element device TTE to close its contact 59 for energizing relay 'I'PS after the eastbound train then leaves section 8T, relay EHDR would become energized by current of reverse polarity by its circuit including contact ZSR-32 and contact 3! of relay ZR. While relay TPS is deenergized, its contact 52 is open, and therefore relay ZR cannot become energized by current of normal polarity although lever ZV has been returned to its n position. Relay SHDR, upon becoming energized, opens the back point of its contact H, thereby deenergizing relay 53R.

When relay TPS becomes energized, its contact PPS-58 opens the stick circuit for relay ZSR, and its contact 52 closes the normal energizing circuit for relay ZR. Contact 51 of relay ZR does not then become closed until after the polar contacts of relay ZR have been returned to the normal position, so that relay ZSR becomes deenergized between the time when contact TPS58 opens and the time when contact 51 of relay ZR closes.

With relay ZR again energized by current of normal polarity, relay ZRP will become energized, so that relay BHDR will again become energized by current of reverse polarity, causing signal [is to display the yellow indication. Relay 8HDR, however, will not again become energized by current of normal polarity until relay ZSR becomes energized after the lapse of a measured period of time, as previously described.

It follows that one purpose of relay TPS and its time element device TTE is to introduce a time interval to permit relay SHDR or relay BHDR to become energized for a brief period of time for restoring relay 58R or relay ESR, re spectively, to its deenergized condition when lever ZV is moved from one of its control positions to the other While relay TP' is deenergized by a train on the stretch of track between the pair of signals 38 and 4S and the pair of signals 1S and 8S.

I have described the operation of the apparatus for a few typical trafiic movements. It is believed that, in view of this description, the operation of the apparatus for any other possible traffic movement can be readily understood by refrence to the drawings.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therien Within the scope of the appended without (1 parting from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a control system for signals for a stretch of single track railway including a first pair of automatic signals adjacent a giyen end of said stretch and a second pair of automatic signals adjacent the opposite end of said stretch, a given signal of each of said pairs arranged for governing traific movements onto said stretch and the other signal of each of said pairs arranged for governing traffic movements ofi of said stretch. and including a pair of automatic intermediate signals between said first and second pairs of signals for governing trafiic movements in opposite directions, the combination comprising, manually controllable means for at times extending the automatic control of one of said given signals and of one of said intermediate signals beyond the end of said stretch in a. given direction to control said one given signal and said one intermediate signal to indicate stop if a track section is occupied beyond the end of said stretch in said given direction, and other manually controllable means for at other times extending the automatic control of the other given signal and of the other of said intermediate signals beyond the end of said stretch in the opposite direction to control said other given signal and said other intermediate signal to indicate stop if a track ection is occupied beyond the end of said stretch in said opposite direction only while said first manually controllable means is inefiective for extending the automatic control of said one given signal and of said one intermediate signal.

2. In a control system for signals for a stretch of single track railway including a first pair of signals for governing trafiic movements in opposite directions adjacent a given end of said stretch and a second pair of signals for governing traific movements in opposite directions adjacent the opposite end of said stretch, and including a pair of intermediate signals for governing traffic movements in opposite directions between said first and second pairs of signals, the combination comprising, manually controllable means for at times arranging for a given signal of said first pair and a signal of said intermediate pair for a given direction of trafiic movements to be controlled to. indicate stop by trafiic conditions in said given direction beyond said second pair of signals as well as by trafiic conditions on said stretch while a given signal of said second pair and the other signal of said intermediate pair for the opposite direction of traffic movements are controlled to indicate stop by traffic conditions on said stretch only, and said manually controllable means at other times arranging for said given signal of said second pair and said other signal of said intermediate pair to be controlled to indicate stop by traffic conditions in said opposite direction beyond said first pair of signals as well as by trafiic conditions on said stretch while said given signal of said first pair and said first signal of said intermediate pair are controlled to indicate stop by traffic conditions on said stretch only.

3. In a control system for signals for a stretch of single track railway including a first pair of signals for governing trafiic movements in opposite directions adjacent a given end of said stretch and a second pair of signals for governi s r ffiv m vements Opposite directions adjacent. the opposite end of said. stretch, the

combination comprising, manually controllable means 'for' at times arranging :for a given signal of said first pair to be controlled to indicate stop if a track section beyond the opposite end of said stretch is occupied as well as if said stretch of track is occupied by a train which is approaching said given signal of said first pairfrom said opposite end of said stretch and for arranging for a given signal of said second pair to indicate stop only'if said stretch of track is occupied by a train which is approaching said given signal of said second pair from said given end of said stretch and only if said manually controllable means is in condition for controlling said given signal of said first pair to indicate stop if said track section beyond said opposite end of said stretch is occupied, and said manually controllable means at other times arranging for said given signal of said second pair to be'controlled to indicate stop if a track section beyond said first pair in said opposite direction is occupied as well as if said stretch is occupied and for at said other times also arranging for said given signal of said first pair to indicate stop only if said stretch is occu-pi'ed.

4. In a control system for signals for a stretch of single track railway including a first pair of signals for governingtraffic movements in oppositedirections adjacent a given end of said stretch anda second pair of signals forgovern-ing traffic movements in opposite-directions adjacent the opposits end of said stretch, the combination comprising, acontrol circuit for a given signal of said first pair controlled by trafiioconditions on said stretch and controlled by a contact which is closed if a track section adjacent said opposite end of said stretch is unoccupied but becoming opened if said track section becomes occupied, a control circuit for a given signal of said second pair controlled by traffic conditions on said stretch and controlled by a second contact which is closed if a second track section adjacent said given end of saidstretch is unoccupied but becoming opened if said second track section becomes occupied, and manually controllable means for at times closing a circuit path around said first contact and for at other times closing a circuit path around said second contact.

5. In a control system for signals for a stretch of single track railway including a first pair of signals for governing trafiic movements in opposite directions adjacent a given end of said stretch and a second pair of signals for governing trafiic movements in opposite directions adjacent the opposite end of said stretch, the combination comprising, a control circuit fora given signal of said first pair controlled by trafiic conditions on said stretch and controlled by a contact which is closed if a track section adjacent said opposite end of said stretch is unoccupied but becoming opened if said track section becomes occupied, a control circuit for a given signal of said second pair controlied by trafiic conditions on said stretch and controlled by a second contact which is closed if a second track section adjacent said given end of said stretch is unoccupied but becoming opened if said second track section becomes occupied, a manually controllable device having a normal and a reverse position, means controlled by said device in its normal position for closing a circuit path around said first contact, and means controlled by said device in its reverse position for closing a circuit path around said second contact.

14 6: In :a control system for signals for a stretch of single track railway including a first pair of signals :for governing traffic movements in oppositedirecti'ons' adjacent a given end of said-stretch and arsecond pair of signals for governing trafiic movements in opposite directions'adjacent the opposite end of said stretch,the combination comprising, a control circuit for a given signal of said'first pair controlled by traffic conditions on said stretch and controlled by a contact which is closed if :a tracksection: adjacent saidopposite end of said stretch is unoccupied but becoming opened if said track section becomes occupied, a control circuit for a vgiven signal of said second 'pair' controlled by trafiic conditions on said stretch and controlled by a second contact which is closed if a second track section adjacent said given end of said. stretch is unoccupied but becoming opened if said second track section becomes occupied, a stick relay, a pick-up and a stick circuit for said stick relay each of which is closed only if said stretch of track is unoccupied and said pick-up circuit also controlled by .a time element device, an energizing circuit for said time element device controlled by a back contact of said stick relay and closed only if said stretohof track is unoccupied, and manually controllable means controlled also by a front contact of said stick relay for at times closing a circuit path around said first contact and for at other times closing a circuit path around said second contact.

1. In a control system for signals for astretch of single track railway including a first pair of signals for governing trafiic movements in opposite directions adjacent a given-end of said stretch and a, second pair-of signals for governing traffic movements in opposite directions adjacent the opposite end of said stretch, the combinationv comprising, a control circuit for a given signal of said first pair controlled by traffic conditions on said stretch and controlled by a first contact which is closed it a track section adjacent said opposite end of said stretch is unoccupied but becoming opened if said track section becomes occupied, a control circuit for a given signal of said, second pair controlled by traflic conditions on said stretch and controlled by a second contact which is closed if a second track section adjacent said given end of said stretch is unoccupied but becoming opened if said second track section becomes occupied, a. stick relay, 2, time element device, a manually controllable device having a normal and a reverse control position, a pick-up circuit for said stick relay controlled by a front contact of said time element device and closed only if both signals of said first pair are controlled to display an indication other than stop, a second pick-up circuit for said stick relay controlled by a front contact of said time element device and including a, contact which is normally closed. if said stretch of track is unoccupied but which becomes opened for a brief period of time when said manually controllable device is moved from either of its control positions to the other, a first and a second stick circuit for said stick relay which are the same as said first and second pick-up circuits respectively except that said stick circuits include a front contact of said stick relay instead of being controlled by a front contact of said time element device, means including a back contact of said stick relay for effecting energization of said time element device, means controlled by said manually controllable device in its normal and reverse positions for closing a circuit path around said first and second contacts respectively in said signal control circuits, and means controlled by said stick relay to prevent clearing either of said given signals until a measured period of time has elapsed after the other given signal has been controlled to display the stop indication.

8. In a control system for signals for a stretch of single track railway including a first pair of signals for governing traflic movements in opposite directions adjacent a given end of said stretch and a second pair of signals for governing traffic movements in opposite directions adjacent the opposite end of said stretch, in which a given signal of each of said pairs is controlled to indicate stop if said stretch of track is occupied, the combination comprising, manually controllable means for at times also controlling one of said given signals to indicate stop if a track section beyond said stretch in the direction of traffic A movements governed by said one given signal is occupied, and other manually controllable means for at other times also controlling the other of said given signals to indicate stop if a track section beyond said stretch in the direction of traffic movements governed by said other given signal is occupied only while said first manually controllable means is ineffective for controlling said one of said given signals to indicate stop if a track section beyond said stretch is occupied.

9. In a control system for signals for a stretch of single track railway including a first pair of signals for governing trafiic movements in opposite directions adjacent a given end of said stretch and a second pair of signals for governing trafiic movements in opposite directions adjacent the opposite end of said stretch, in which a given signal of each of said pairs is controlled to indicate stop if said stretch of track is occupied, the combination comprising, manually controllable means for at times also controlling one of said given signals to indicate stop if a, track section beyond said stretch in the direction of traifia movements governed by said one given signal is occupied and for at other times also controlling the other of said given signals to indicate stop if a track section beyond said stretch in the direction of traflic movements governed by said other given signal is occupied, and time element means controlled by said manually controllable means to delay clearing either of said given signals for a measured period of time if the other of said given signals is controlled by said manually controllable means to indicate stop.

10. In a control system for signals for a stretch of single track railway including a, first pair of signals for governing trafi'ic movements in opposite directions adjacent a given end of said stretch and a second pair of signals for governing traflic movements in opposite directions adjacent the opposite end of said stretch, in which a given signal of each of said pairs is controlled to indicate stop if said stretch of track is occupied, the

combination comprising, a manually controllable device having a normal control position for at times also con-trolling one of said given signals to indicate stop if a track section beyond said stretch in the direction of traffic movements governed by said one given signal is occupied and having a reverse control position for at other times also controlling the other of said given signals to indicate stop if a track section beyond said stretch in the direction of traffic movements governed by said other given signal is occupied, and means controlled by said manually controllable device upon being moved from either of its control positions to the other for delaying the clearing of either of said given signals for a measured period of time if the other of said given signals is controlled by said manually controllable device to indicate stop.

WILLIAM H. CLAUS.

REFERENCES CITED UNITED STATES PATENTS Name Date Wight Mar. 3, 1931 Number 

